Immunology School Listings Home            

   Immunology Schools Feedback Feedback

Immunology Schools Feedback
ImmunologySchool Listings
Immunology Careers
Free Course on Immunology
Immunology Schools Examination
Immunology Schools FAQs
Anatomy Top Schools/School Rankings
Anatomy Top Schools/School Rankings

Haemophilus


ORGANISM:

  • Genus: Haemophilus
  • Species: influenzae


GENERAL CONCEPTS:
  • Haemophilus influenzae is responsible for producing a variety of infections including meningitis and respiratory infections.
  • Six serological types (a,b,c,d,e,f) based on the antigenic structure of the capsular polysaccharides are recognized. Nonencapsulated strains are (by definition) nontypable.
  • Other species of Haemophilus include: H. parainfluenzae (pneumonia, endocarditis), H. ducreyi (venereal chancre) and H. aegypticus (conjunctivitis).


DISTINCTIVE PROPERTIES:
  • The genus Haemophilus is composed of Gram-negative coccobacilli.
  • These organisms are fastidious and require factors X (hemin) and/or V (NAD).
  • Haemophilus possess LPS in the cell wall but produce no apparent extracellular toxins.


PATHOGENESIS:
  • The organisms colonize the nasopharynx and are spread by direct contact. Haemophilus are capable of penetrating the epithelium to produce a bacteremia that may lead to localization of the organisms in many organs. The capsule is Haemophilus' major virulence determinant yet unencapsulated strains produce ear, sinus and respiratory infections.
  • H. influenzae type b is the most common cause of bacterial meningitis in children aged 6 months-2 years. It is uncommon in adults because of protective antibody.
  • Cellulitis, conjunctivitis, epiglottitis and arthritis may also result from Haemophilus infection.
  • For pneumonia in adult men, unencapsulated H. influenzae is second only to the pneumococcus (S. pneumoniae). Those affected are usually chronic smokers, alcoholics or elderly.


HOST DEFENSES:
  • Antibody directed against the polyribosyl-ribitol-phosphate (PRP) capsule is bactericidal.


EPIDEMIOLOGY:
  • Spread of Haemophilus is human to human. Day care centers are common sites for transmission from healthy, unaffected adults to susceptible infants.


DIAGNOSIS:

  • Clinical: A Gram stain of cerebrospinal fluid may reveal the organisms. One can also detect capsular material directly.
  • Laboratory: The organisms are cultured on chocolate agar because it contains both factors X and V. Incubation in 10% CO2 is required.


CONTROL:

  • Sanitary: Avoidance of carriers is not always possible.
  • Immunological: A vaccine against type b is available. Unfortunately, the vaccine is nonimmunogenic in infants where it is needed the most.
  • Chemotherapeutic: Third generation cephalosporins are probably the drugs of choice because of their ability to cross the blood-brain barrier and their bactericidal activity.

Our Network Of Sites:
Apply 4 Admissions.com               | A2ZColleges.com  | OpenLearningWorld.com  | Totaram.com
Anatomy Colleges.com                 | Anesthesiology Schools.com  | Architecture Colleges.com | Audiology Schools.com
Cardiology Colleges.com            | Computer Science Colleges.com | Computer Science Schools.com | Dermatology Schools.com
Epidemiology Schools.com          | Gastroenterology Schools.com  | Hematology Schools.com     | Immunology Schools.com
IT Colleges.com                | Kinesiology Schools.com  | Language Colleges.com  | Music Colleges.com
Nephrology Schools.com             | Neurology Schools.com  | Neurosurgery Schools.com | Obstetrics Schools.com
Oncology Schools.com    | Ophthalmology Schools.com | Orthopedics Schools.com       | Osteopathy Schools.com
Otolaryngology Schools.com | Pathology Schools.com  | Pediatrics Schools.com   | Physical Therapy Colleges.com
Plastic Surgery Schools.com | Podiatry Schools.com   | Psychiatry Schools.com   | Pulmonary Schools.com 
Radiology Schools.com | Sports Medicine Schools.com | Surgery Schools.com  | Toxicology Schools.com
US Law Colleges.com | US Med Schools.com | US Dental Schools.com

Copyright 2000-2011 Immunology Schools, All Right Reserved. | Site Map | Privacy Policy | Disclaimer